The technique of photogrammetry will be used to measure the changes of the optic disc characteristic of glaucoma. Cupping of the optic disc will be correlated with visual functions and clinical course of the patient as indicated especially by ocular pressures and visual fields. The quantitative and objective analysis of optic disc cupping obtained by photogrammetry will be evaluated in diagnosing glaucoma before visual field defects occur. Photogrammetric measurements will also be used in monitoring the effectiveness of medical and surgical modalities in controlling the disease. In order to simplify the process of detecting cup changes, a new subjective screening method, stereochronoscopy, will be studied and reliability will be evaluated with photogrammetry. In addition, a new screening device which can objectively quantitate cup changes with stereochronoscopy will be developed and studied.